Electron discharge device circuit arrangement



April 18, 1933. A. HYLAND ELECTRON DISCHARGE DEVICE CIRCUIT ARRANGEMENTFiled May 6, 1929 iyl|!llllll llllmllllillk 7 g. d I 6 .l 1 L W A! w V 7M W 2 5 ./0/v I h M 4 7 AA. 0/0 fi TIE:- 5

INVENTOR Yaw/mm a,J%G VM,

I ATTORNEY Patented Apr. 18, 1933 UNITED, STATES PATENT .oFrI'cs YLAWRENCE A. HYLAN or wasnmoron, DISTRICT or COLUMBIA, AssreNon 'rowiniin RADIO, INQ, OF NEW YORK, N. Y.,

A CORPORATION or DELAWAR ELECTRON DISCHARGE DEVICE CIRCUIT ARRANGEMENTApplication 'filed May 6, 1929. Serial No. 360,904.

I My invention relates broadly to electron discharge devices and morespecifically tov electron discharge devices employed for controlling theresistance of circuits.

One of the objects of my invention is to provide an electron dischargedevice circuit arrangement whereby the resistance of circuitsconnectedwith the electron discharge device may be controlled.

Another object of my inventionis to pro vide an electron dischargedevice circuit arrangement wherein the resistance of-circuits connectedwith the electron discharge device may be varied continuously throughoutwideranges. 7

Still another object ofmy invention is to provide an electron dischargedevice circuit arrangement in which a space discharge deviceis employedto-control the conditions of operation. V g

' A further object of my invention is to provide an electron dischargedevice circuit arrangement for generating electrical oscillations inwhich an electron discharge device is employed to control the magnitudeof the oscillations.

Still a further object of my invention-is to provide an electrondischarge device circuit arrangement for receiving signaling energy,inwhich the regenerative condition may be readily controlled.

A still further, object of my invention is to provide an electrondischarge device sig nal receiving circuit arrangement wherein a spacedischargedevice which is energized from the sources of current supplyemployed to energize the circuits of the signal receiving circuit isusedto control conditions of operation of the receiving circuit.

Another and further object ofmy invention is to provide a circuitarrangement employing electron discharge devices having cathodeelectrodesenergized from a common'source of current supply inwhich oneofthe electron discharge devices is employed to control the magnitude ofthe current flow ing throughthe anode circuits of theother electrondischarge devices. 7

Still another and further object of my invention is to provide a spacedischarge device arrangement for controlling the resist- I ance ofelectrical circuits connected therewith, in which an electron emittingelectrode is substantially electrically isolated from the circuits ofthe electrode which acts to maintain the electron emitting electrode inoperative condition. 7 I

Other objects and features of my invention will be apparent from thefollowing specification and accompanying drawing. According to myinvention anelectron dis,- charge device having a cathode, which isheated through the action of'an-electrode electrically isolatedtherefrom, a grid electrode and an anode is employed in a circuit arerangement as a continuously variableresist ance device. I A source ofpotential is connected'with the cathode. A potentiometer is connectedbetweenthe grid electrode andthe source of potential whereby the gridelectrode maybe maintainedat anyone of an infinite number of diflerentpotentials with-respect to the cathode and the resistance of theelectron current path between cathode and the anode may be variedf z Myinvention is employed to considerable advantage in controlling theregenerative condition of receiving circuits, employingthe well knownfeed back principle, in which the part of the energy of the outputcircuit is transferred to the input circuit so as to augment theelectrical oscillations of theJin-l putcircuitr It is, however, to beunderstood that my'invention is readily adapted for use in controllingvarious amplifying circuits in which the tendency of the circuit togenerate self excited oscillation is due only to the in=' herentinter-electrode capacities. The arrangement of my invention is likewisereadily adapted for use as a sound intensity control or output controlin radio signal receiving sets aswill be seen from'the following: de-

scription.

' In the drawingfF ig'ure 1 illustrates'the ircuit arrangement oftheelectron discharge device variable resistor; Fig.2 illustrates anembodiment of this invention and Fig. 3 illustrates a modified form ofthis invention.

Referring to Fig.; 1 of the drawing indetail, reference numeral 1designates an elecposed'within the device 1. A source 6 of currentsupply is connected to the heating 7 electrode 3. Source 7 of relativelyhigh po- 10 tential is connected to the potentiometer 8. A variablecontact 866 of the potentiometer is connected to the grid electrode 1whereby the negative potential at which the grid electrode is maintainedwith respect to the cathode may be varied. The tap 8?) on potentiometer8 connects to the cathode 2 and enables a selected potential to beimpressed on the oathode from source 7. V

In Fig. 2 an arrangement wherein the apparatus of Fig. 1 is employed tocontrol the output circuit resistance of the electron d1scharge device 9is illustrated. A source 10 of anode current supply for the device 9 15connected to the anode of the device 1. A choke coil 11 is provided inthe output circuit of device 9 between the inductance 12 which isconnected to the anode 9a and the cathode 2 of device 1. A highfrequency bypass condenser 13 is connected betweenthe inductance 12 andthe cathode'of device 9.

Grid leak and grid condenser 14 are connected to the grid electrode 9gand the oscillatory circuit comprising capacity 15 and 1nductance 16.Where the device 9 is employed as'ahigh or low frequency amplifier thegrid leak resistance and the grid condenser 14 are generally eliminated.A source 18 of current supply for heating the cathode 9f and the heatingelectrode 3 is connected into the c rcuits of devices 1 and 9 throughthe current limiting'resistance units 17 and 19. The operation of thecontinuously variable resistance arrangement including the electrondischarge device 1 is as follows:

The anode 5 is connectedwith the positive terminal of the source 10. andthe heater electrode 8' is connected with the negative terminal of thesource whereby an electrostatic field is set up between the electrode 3and the anode 5. Electrons are caused to stream from the electronemitting surface of electrode 2. Through the action of the electrostaticfield the electron stream passes to the anode 5 and gives rise to acurrent'flow in the cathode anode circuit of device 9. By introducingeither a positive or negative potential on the grid electrode 1 withrespect to the electrode 2 the quantity of electrons, that are emittedby the electrode 2, that finally reaches the anode 5, is varied. Theresistance of the electron discharge device 1 is thus varied. Inpractice it is usually desirable to maintain the grid electrode 4: at anegative potential with respect to the electrode 2.

' However in certaincircuit arrangements such as illustrated in Fig. 3of the drawing,- in which the source of current supply 7 a is employedin conjunction with the source of supply 10 as a source of anode currentfor the device 9, it is desirable to maintain the grid electrode at,slight'positive potentials with respect to the cathode 2. I

The source 18 which is employed for the purpose of heating the cathodeelectrodes of devices 1 and 9 may be of'any of a variety of well knowndirect'current or alternating current sources. v v Y Y While I havedescribed my invention in certain of its embodiments it is to beunderstood that various modifications thereof may be madewithoutdeparting from the scope and spirit of this invention, andtherefore I do not desire'to limit this invention to the exact detailsas set forth in the foregoing specificatlon except in so far as they aredefined by the appended claims.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is as follows: v i

1. In an electron tube system, an electro tube havlng anode,grid andcathode, a second electron tubehaving anode, grid, cathode and heaterelectrode, said heater electrode being in thermal relation with the vcathode of said second tube but electrically insulated therefrom, theanode of said first mentioned tube being connected to the cathode ofsaid second mentioned tube, an input c rcuit connecting the gridlof saidfirst mentioned tube to its cathode, a source of anode potential havingits negative terminal connected to the cathode of said first mentionedtube and having its positive terminal co'nnectedto the anode of saidsecond ment oned tube, an independent source of grid biasingpotential,and a voltage divider connected for variably applying a portion of saidbiasing potential between the cathode and grid of said second tube.

2. In an electron tube system, an electron tube having anode, grid andcathode, a second electron tube having anode, cathode and heaterelectrode, said heater electrode being in thermal relation with thecathode of said second tube but electrically insulated therefrom, theanode of said first mentioned tube being connected to the cathode of'saidsecond mentioned tube, an input circuit connecting the grid of saidfirst mentioned tube to its cathode, a source of anode potential havingits negative terminal connectedto the cathode of said first mentionedtube and having its positive terminal connected to the anode of saidsecond mentioned tube, and a common source of potential for energizingthe cathode of said first mentioned tube and th'g heater electrode ofsaid second mentioned tu e. i

3. In an electron tube system, an electron tube having anode, grid andcathode, a see.

ond electron tube having anode, grid, cathode and heater electrode, saidheater electrode being in thermal relation with the cathode of saidsecond tube but electrically insulated therefrom, the anode of saidfirst mentioned tube being connected to the cathode of said secondmentioned tube, an input circuit connecting the grid of said firstmentioned tube to its cathode, a source of anode potential having itsnegative terminal connected to the cathode of said first mentioned tubeand having its positive terminal connected to the anode of said secondmentioned tube, an independent source of grid biasing potential, avoltage divider connected for variably applying a portion of saidbiasing potential between the cathode and grid of said second tube, anda common source of potential for energizing the cathode of said firstmentioned tube and the heater electrodeof said second mentioned tube.

LAWRENCE A. HYLAND.

